1. Field of Invention
The present invention relates to an installation for supplying gas in a semiconductor manufacturing reaction chamber. More particularly, the present invention relates to an installation for adjusting gas supply in a semiconductor manufacturing reaction chamber according to an environmental condition in the reaction chamber.
2. Description of Related Art
Integrated circuits are manufactured with sub-micron dimensions while the size of wafers from which the circuits are produced is increased. In this situation, it is important to control the uniformity of reacting plasma, which is closely related to the uniformity and the microloading effect of the wafer. The microloading effect is a condition in which different etching rates and depositing rates occur while etching or forming a thin film on the wafer due to the exposed areas of a pattern. Provision of a uniform gas flow from a gas source is an important issue in the development of semiconductor technique.
FIG. 1 shows a schematic, cross-sectional view of a conventional installation to supply gas in a reaction chamber 100. The reaction chamber 100 is installed with a gas-supplying panel 110 and a negative electrode 115. The gas-supplying panel 110 is installed under the top cover 118 of the reaction chamber 100. A wafer 120, which is to be reacted, is placed on the negative electrode 115. The reaction chamber 100 possesses an outlet 130, which is coupled to a pump 150 through a valve 140. When the pump 150 is operating, gas in the reaction chamber 100 is drawn into the pump 150, by which action a vacuum is maintained in the reaction chamber 100. Furthermore, reacting gases are introduced into the reaction chamber 100 through the gas-supplying panel 110 to react with the wafer 120 deposit a thin film or etch the wafer. Hereinafter the function of the gas-supplying panel 110 is introduced in detail, and is further illustrated in FIG. 2.
FIG. 2 shows a schematic, top view of the gas-supplying panel 110 as shown in FIG. 1. The gas-supplying panel 110 has a plurality of symmetric apertures 112 and is circular. The apertures 112 are symmetrically arranged with respect to the center point of the gas-supplying panel 110. Reacting gases can be introduced into the reaction chamber 100 through the apertures 112 of the gas-supplying panel 110 that is installed under the top cover 118 of the reaction chamber 100. Because the apertures 112 are located symmetrically in the gas-supplying panel 110, the reacting gases are uniformly introduced and distributed into the reaction chamber 100. However, the interior of the reaction chamber 100 is asymmetrical due to installations in the chamber, and thus the gas flow of the gases introduced into the reaction chamber 100 is not uniform while performing the desired etching or deposition process. Furthermore, when the pump 150 is operated to maintain the vacuum of the reaction chamber 100, the disturbances in the flow of the reacting gases is even more distinct. Because of the disturbed gas flow, the uniformity and microloading effect of the wafer 120 are seriously affected, which causes a grave decrease in the manufacturing yield the uniformity of the dies in the wafer.
In light of the foregoing, there is a need to provide an installation for the reaction chamber that avoids the drawbacks described above.